[mythtv-users] Do I understand MythTV correctly?

[Michael T. Dean]

lawrence.mandel at utoronto.ca wrote:

>I can setup a MythTV backend on a P4, 2GHz, 512 Megs, and large HDD with two 
>Hauppauge 250 cards (no sound card?). One card will be connected to a digital 
>cable box and the other to regular cable. The one connected to the digital 
>cable box can be configured (with some sort of IR device) to control the cable 
>box.
>
Yep.

>I can then setup one or more frontends on other machines (Hauppauge 350 
>card and SB live with 5.1 surround) and connect via ethernet to the backend.
>
Actually, a "frontend" with a PVR-350 is really a backend/frontend.  The 
backend is simply a Myth box that has a tuner card which can be used to 
capture video from cable/composite/S-Video.  The PVR-350 has a tuner and 
a hardware encoder and a hardware decoder (with TV out).  The PVR-250 
has a tuner and a a hardware encoder (so you definitely don't need a 
PVR-350 on a dedicated backend).

If you're planning to just use the PVR-350 for it's TV out, it would be 
much cheaper to go with some other video card with TV out.  If you're 
intrigued by reports of stunning picture quality on the PVR-350 (and it 
is) and don't mind the occasional instabilities, go for the PVR-350, but 
remember each one can take the place of a PVR-250.

>The frontends will have full functionality and be able to view recorded 
>programs and live tv (by selecting the source from the backend.)
>  
>
Right, as long as you have an available tuner card (i.e. someone else 
isn't using it for watching TV/recording), you can grab it--even across 
the net.  If you don't have an available tuner card (i.e. all your 
tuners are recording/playing LiveTV on other frontends), you can watch 
recordings--even if the recording you want to watch is currently in 
progress.

>Is this right? Can MythTV do all of this?
>  
>
Can you say, "tip of the iceberg."  ;)

>If so I have a few questions.
>
>1. What would you recommend to use for the backend machine? I would guess a 
>P4, 2GHz, 512 Megs, large (>100Gig) HDD and two Hauppauge 250 cards will work. 
>Should/can I use a more/less powerful machine? Do I need half a gig of ram?
>  
>
If it's a dedicated backend with PVR-250's, you won't need that kind of 
processor power.  Memory can be useful--especially if you run a lot of 
services on the machine, but 256MB may be plenty (however, the memory is 
probably much more useful than a powerful processor).

If you put a PVR-350 in all your frontends, you might not need the 
dedicated backend.  You could just run MySQL/NFS on a machine on the 
network.  However, it never hurts to have more tuners...

>2. At what point should I look at adding a slave backend machine rather then 
>upgrading the single backend machine?
>  
>
You were looking when you started talking about the frontend with a 
PVR-350.  :)

>3. Has anyone connected the frontends wirelessly to the backend? Does 802.11b 
>work ok or do I need to use 802.11g?
>  
>
It works, but due to many factors--i.e. signal strength, amount of other 
traffic on the network, encoding format (i.e. MPEG-2 produced by the 
PVR-x50's can take as much as twice the bandwidth of MPEG-4 software 
encoded using a frame grabber, but both are much smaller than "raw" 
RTJPEG encoded from a frame grabber).  I've heard that 802.11b is 
acceptable for a single video at a time, and it sounds like you're 
interested in having multiple frontends.  I'd say invest $50 in a box of 
Cat 5e and start running cables (that's what I did).

>4. This is the where do people recommend going for hardware question. I want 
>my frontends to look cool (not a crappy beige box.) Anyone know of a good 
>computer shell shop? Preferably something thin. How about a good shop for 
>purchasing the rest of the hardware I need?
>  
>
No recommendations.  I'm more the cheap-beige-box kind of guy. :)

>5. Finally, from what I've read it's safest to use Hauppauge 250 and 350 cards 
>but they do cost more then other cards. Can anyone recommend other TV input 
>and TV output (with COAX connection) cards? I don't want to sacrifice audio 
>and video using MythTV.
>  
>
For TV output, a lot of people are using the GeForce 4 MX 440 (but I'm 
pretty sure it doesn't have an F-Connector on it.  Then again, I don't 
know of any cards with COAX output through an F-connector.)  As far as 
input goes, I've got a PVR-350, but if I knew then what I know now, I 
would have bought a PVR-250 instead.  The 350 is great, but you lose Xv 
(for DVD's, QT, WMP, XviD, DivX, etc.) and hardware accelerated 2D and 
3D graphics (for games, MythMusic visualizations, etc.).

Mike